Industrial silicon carbide is generally produced by a discontinuous or batch process in a furnace typically of the electrical resistance type. Silicon carbide production is important because silicon carbide is considered a strategic stockpiled material by the government. The process generally involves mixing raw materials of silica, sand and petroleum coke and placing these materials in an electric resistance furnace. The reaction is then carried out by direct electrical heating. As a result of the process, various by-product waste gases consisting primarily of carbon monoxide, carbon dioxide and hydrogen are produced in large amounts. Other by-product waste gases, such as hydrogen sulfide and hydrocarbons such as methane also form from the impurities in the coke.
U.S. Pat. No. 3,976,829 discloses a gas collection system developed in the late 1970's for use with an electrical resistance furnace of the type disclosed in U.S. Pat. Nos. 3,950,602, 3,989,883 and 4,158,744. The gas collection system allows collection of the by-product waste gases during the manufacture of silicon carbide for subsequent incineration. During incineration the gases are converted into carbon dioxide and sulfur dioxide and then emitted into the atmosphere.
However, carbon dioxide and sulfur dioxide are pollutant gases, and emission thereof into the atmosphere is regulated for health and environmental reasons. In this connection, evolution of sulfur dioxide into the atmosphere is presently scrutinized in connection with the "acid-rain" effect. Many processes are available for removing the sulfurous contaminants from the gases. But these processes generally are costly in capital investment and wasteful in energy conservation. Furthermore, evolution of carbon dioxide into the atmosphere is presently scrutinized in connection with the "green-house" effect. Therefore, an economical system and method of converting environmentally pollutant by-product waste gases, such as hydrogen sulfide and carbon monoxide emitted during the manufacture of silicon carbide, whereby evolution of the gases into the atmosphere may be prevented would be desirable. Furthermore, the storage of the by-product gases for later use in a manufacturing process requires uneconomical storage handling steps. Therefore, it is desirable, to avoid storage while advantageously converting the by-product waste gases into useful products wherein they are not disadvantageously emitted to the atmosphere.